Diffusion-weighted imaging (DWI) is a specialized magnetic resonance imaging (MRI) technique that provides valuable information about the movement of water molecules within tissues. It is particularly useful for assessing the microstructural characteristics of tissues and detecting abnormalities in various medical conditions. In DWI, the MRI sequence applies diffusion-sensitizing gradients to the imaging process, allowing the visualization of the random motion of water molecules. This technique is highly sensitive to changes in tissue cellularity and integrity, making it especially effective in oncology for identifying and characterizing tumors, evaluating treatment response, and detecting metastatic lesions. Beyond oncology, DWI has applications in neuroimaging, where it aids in the early diagnosis of stroke, evaluation of neurodegenerative disorders, and assessment of inflammatory conditions affecting the brain and spinal cord. The versatility of DWI is further demonstrated in its utility for abdominal imaging, particularly in evaluating liver and pancreatic diseases. In the liver, DWI helps assess tissue vascularity, detect focal lesions, and differentiate benign from malignant lesions. In pancreatic imaging, DWI assists in characterizing pancreatic tumors and assessing their relationship with surrounding structures.
The quantitative nature of DWI, as seen in parameters like apparent diffusion coefficient (ADC), adds an additional layer of information for clinicians to interpret and aids in refining diagnoses. Ongoing research continues to explore and optimize DWI protocols, and its integration with other advanced imaging techniques enhances its diagnostic capabilities across various medical disciplines. As a non-invasive imaging modality, DWI has become an indispensable tool in clinical practice, offering unique insights into tissue microstructure and function. Its ability to provide information on cellular density and tissue organization makes DWI a valuable asset in the armamentarium of diagnostic radiology, contributing to the comprehensive assessment of diseases and guiding therapeutic decision-making in a wide range of medical specialties.